Clinical studies suggest that cholinesterase inhibitors (ChEIs) exert a cognitive benefit with chronic use among MCI and AD patients. Some studies also demonstrate a slight treatment benefit for persons who are APOE 4 positive. We propose to conduct a 24-week, randomized, double-blind, placebo-controlled, parallel group study of the Exelon® \[rivastigmine\] transdermal patch in 120 aMCI patients who have one or both APOE 4 alleles. Our preliminary analyses indicate that aMCI patients, even those who convert to AD, exhibit increased fMRI activation on our semantic memory activation task relative to not at-risk healthy participants and that increasing activation over time correlates with declines on neuropsychological testing. In addition, our preliminary data indicate that ChEI treated aMCI patients demonstrate normalization (i.e. reduction) in the magnitude of task-related neural activation over time relative to an untreated group. Furthermore, changes in fMRI magnitude demonstrated greater sensitivity to cholinergic modulation than changes on neuropsychological testing.
